Polymer Composite Containing Recycled Carbon Fibers

ABSTRACT

A polymer composition is described well suited for being combined with relatively short fibers. The fibers, for instance, can have a mean fiber length of less than 1,000 microns, such as less than 700 microns, such as less than 500 microns. The polymer formulation allows for intimate mixing with the fibers without having to use a sizing agent. In one embodiment, the composition contains a polybutylene terephthalate polymer combined with a thermoplastic polymer having lower crystallinity.

RELATED APPLICATIONS

The present application is based upon and claims priority to U.S.Provisional Application Ser. No. 62/628,037, having a filing date ofFeb. 8, 2018, which is incorporated herein by reference in its entirety.

BACKGROUND

Engineering thermoplastics are often reinforced with fibrous fillers inorder to increase the modulus of parts and products made from thereinforced composition. Adding fibers to thermoplastics can alsoincrease the tensile strength of the materials. Increasing the tensilestrength increases the maximum force necessary for the part or productto break.

Recently, the automotive industry has focused on making many automotiveparts from carbon fiber composites in order to reduce weight. In orderto make many of these parts, a carbon fiber fabric, scrim or mat isfirst assembled and then impregnated with a reactive resin (e.g. epoxy,unsaturated polyester, etc.), which is later cured. The resulting partsmade from the material are not only lightweight, but have excellentphysical properties. Lowering the weight of the overall vehicle cansignificantly improve fuel economy standards.

Unfortunately, however, the process produces a significant amount ofcarbon fiber scrap. For instance, in some processes, from about 10% toeven over 50% of the carbon fiber is in the form of scrap.

In order to recycle the unused carbon fibers, the carbon fiber scrap istypically fed through a process that reduces the scrap to individualcarbon fibers. For instance, in one embodiment, the scrap may be fedthrough a hammer mill in order to achieve fiber separation. The fiberseparation process, however, can significantly reduce the fiber lengthand can fracture the fibers.

Problems have been experienced in the past in incorporating the recycledcarbon fibers into a thermoplastic matrix that has the desired balanceof properties. For instance, thermoplastic composites made from recycledcarbon fibers may have relatively high tensile strength properties butmay have relatively low elongation at break properties. The elongationat break properties, for instance, may be undesirably low due to thefiber damage that occurs during recycling and due to a weak fiber-matrixadhesion. In order to improve the fiber-matrix adhesion, a sizing agentmay be applied to the fibers. Using a sizing agent, however, not onlymakes the process more labor and energy intensive, but also can make theprice of products made from the process exorbitantly high.

In view of the above, a need exists for a polymer composition andprocess that incorporates recycled carbon fibers and produces parts andarticles having a desired balance of physical properties.

SUMMARY

In general, the present disclosure is directed to polymer compositionscapable of being combined with relatively short fibers, such as recycledcarbon fibers. The fibers can be incorporated into the composition inorder to produce articles and parts with good mechanical properties andwithout having to treat the fibers with a sizing agent.

In one embodiment, the present disclosure is directed to a reinforcedpolymer composition containing at least one polyester polymer. In oneembodiment, for instance, the polymer composition contains a firstpolyester polymer combined with or blended with a second polyesterpolymer. In accordance with the present disclosure, the second polyesterpolymer can be less crystalline than the first polyester polymer. Forinstance, in one embodiment, the first polyester polymer may have acrystallinity of greater than about 38%, such as greater than about 40%,such as greater than about 45%. The second polyester polymer, on theother hand, may have a crystallinity of less than, about 40%, such asless than about 38%, such as less than about 35%, such as less than 32%.The first polyester polymer may be present in the composition in anamount of at least about 20% by weight, such as in an amount of at leastabout 30% by weight, such as in an amount of at least about 40% byweight. The first polyester polymer is generally present in an amountless than about 90% by weight, such as in an amount less than about 85%by weight, such as in an amount less than about 80% by weight, such asin an amount less than about 70% by weight. When present, the secondpolyester polymer can be contained in the composition in an amount from5% to about 40% by weight.

In accordance with the present disclosure, the one or more polyesterpolymers are combined with carbon fibers, such as recycled carbonfibers. The carbon fibers can have a mean fiber length of from about 10microns to about 1,000 microns, such as from about 50 microns to about700 microns, such as from about 50 microns to about 400 microns. Forexample, the mean fiber length before compounding may be less than about700 microns, such as less than about 500 microns, and also greater thanabout 100 microns. After compounding, the mean fiber length may be, forexample, less than about 500 microns, such as less than about 400microns, such as less than about 200 microns and generally greater than50 microns.

The carbon fibers can be present in the polymer composition in an amountfrom about 5% to about 50% by weight, such as in an amount from about10% to about 44% by weight. In one embodiment, the carbon fibers aresubstantially free of a sizing agent. For instance, in one embodiment,the carbon fibers may be untreated and contain no sizing agent.

The first polyester polymer present in the composition may comprise apolybutylene terephthalate polymer. As stated above, in one embodiment,the polymer composition may contain a second polyester polymer havinglower crystallinity. The second polyester polymer, for instance, maycomprise a polybutylene terephthalate, a polyethylene terephthalate, ora copolyester.

In one embodiment, the reinforced polymer composition of the presentdisclosure comprises a blend of at least one polyester polymer, carbonfibers such as recycled carbon fibers, a fatty acid ester such as anester of montanic acid, a nucleant such as talc, a heat stabilizingagent, and an antioxidant. The heat stabilizer may comprise adiphosphite or triphosphite. The antioxidant may comprise a stericallyhindered phenolic compound.

The polymer composition may be compounded by any compounding methodknown in the art, such as melt blending, mixing, extruding, or othersuch methods, used alone or in combination.

An almost limitless variety of different products and parts can be madefrom the polymer composition of the present disclosure. For example, thepolymer composition is particularly well suited to producing housingsthat comprise a molded polymer article made from the polymercomposition. The housing may have a shape configured to enclose anadjacent structure. The housing, for instance, may comprise a housingfor a motor. When formed into a housing, the housing is particularlywell suited for being used as an automotive part in the enginecompartment or elsewhere in the vehicle. In one embodiment, forinstance, the housing may be part of a wiper blade assembly.

The polymer composition used to produce the housings can have a tensilestrength of greater than about 110 MPa, such as greater than about 120MPa, such as greater than about 130 MPa, such as greater than about 140MPa. The polymer composition can have a tensile modulus of greater thanabout 12,000 MPa, such as greater than about 12,500 MPa, such as greaterthan about 13,000 MPa, such as greater than about 14,000 MPa. Thepolymer composition may also exhibit an elongation at break of greaterthan about 2%, such as greater than about 2.5%, such as greater thanabout 3%, such as greater than about 3.5%, such as greater than about4%.

Other features and aspects of the present disclosure are discussed ingreater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present disclosure is set forthmore particularly in the remainder of the specification, includingreference to the accompanying figures, in which:

FIG. 1 is a perspective view of a vehicle engine illustrating variousmolded polymer parts that may be made in accordance with the presentdisclosure.

Repeat use of reference characters in the present specification anddrawings is intended to represent the same or analogous features orelements of the present invention.

DETAILED DESCRIPTION

It is to be understood by one of ordinary skill in the art that thepresent discussion is a description of exemplary embodiments only, andis not intended as limiting the broader aspects of the presentdisclosure.

The present disclosure is generally directed to fiber reinforced polymercompositions containing relatively short reinforcing fibers. The polymercomposition of the present disclosure, for instance, is particularlywell suited to incorporating recycled carbon fibers into the polymermatrix. Of particular advantage, the polymer composition of the presentdisclosure can synergistically combine with the carbon fibers in amanner that produces products having a good combination of physicalproperties without having to apply a sizing agent to the fibers.

In general, the polymer composition of the present disclosure containsat least one polyester polymer blended with relatively short fibers. Thefibers, for instance, can have a mean fiber length of less than about1,000 microns, such as less than about 700 microns, such as less thanabout 500 microns, such as less than about 400 microns, such as evenless than about 100 microns. The fibers generally have a length ofgreater than about 10 microns, such as greater than about 50 microns.For example, the mean fiber length before compounding may be less thanabout 700 microns, such as less than about 500 microns, and also greaterthan about 100 microns. After compounding, the mean fiber length may be,for example, less than about 500 microns, such as less than about 400microns, such as less than about 200 microns.

As used herein, the mean fiber length is determined generally accordingto ISO Test No. 22314 (First Edition, May 1, 2006). However, as usedherein, the fiber length is determined semiautomatically. In particular,magnified images according to Section 6.3 of ISO Test 22314 are capturedwith a high resolution scanner and analyzed using IMAGE PRO PLUS pictureanalysis software. Three to five frames are evaluated for each sample.The determination of the length of the individual fibers is done in anautomated way by the above software.

The at least one polyester polymer comprises a polybutyleneterephthalate. In one embodiment, the polybutylene terephthalate iscombined with a second thermoplastic polymer. The second thermoplasticpolymer may also comprise a polyester polymer. The second thermoplasticpolymer has a lower crystallinity than the polybutylene terephthalate.The polymer composition can also contain various other components suchas a nucleant, a fatty acid ester, and one or more stabilizing agentsand/or antioxidants.

The polymer composition of the present disclosure is well suited tobeing formed into various different polymer articles, including partsand products. In one embodiment, for instance, the polymer compositionmay be used to produce automotive parts, such as housings.

Referring to FIG. 1, for instance, various polymer articles made inaccordance with the present disclosure are shown. For example, in oneembodiment, the polymer composition can be used to produce housings 10,12 and 14. The housings have a shape so as to enclose an adjacentstructure. In FIG. 1, for instance, housing 10 comprises an enginecover.

In other embodiments, the housing can be used to enclose a motor orother component. In one embodiment, for instance, as shown in FIG. 1,the housing 16 can be part of a wiper blade assembly. The housing can beused to cover the motor of the wiper blade or can be used to cover aportion of the wiper blade itself.

In still another embodiment, the housing may be used to cover a motor ofa power window assembly.

When used to construct a housing as described above, the polymercomposition of the present disclosure can have a desired balance ofproperties. For instance, the polymer composition can have a tensilestrength of greater than about 110 MPa, such as greater than about 120MPa, such as greater than about 130 MPa, such as greater than about 140MPa, such as greater than about 150 MPa, such as even greater than about180 MPa, or even greater than about 200 MPa. The tensile strength of thepolymer composition is generally less than about 350 MPa. The polymercomposition can have a tensile modulus of greater than about 12,000 MPa,such as greater than about 12,500 MPa, such as greater than about 13,000MPa, such as greater than about 14,000 MPa, such as greater than about15,000 MPa, such as greater than about 16,000 MPa, such as greater thanabout 17,000 MPa, such as greater than about 18,000 MPa, such as evengreater than about 20,000 MPa. The tensile modulus is generally lessthan about 40,000 MPa, such as less than about 35,000 MPa. Of particularadvantage, the polymer composition can have the above tensile strengthand tensile modulus properties while having desired elongationproperties. For instance, the polymer composition may display anelongation at break of greater than about 2%, such as greater than about2.3%, such as greater than about 2.5%, such as greater than about 2.8%,such as greater than about 3%, such as greater than about 3.5%, such aseven greater than about 4%. The elongation at break is generally lessthan about 10%, such as less than about 8%.

In one embodiment, the composition comprises a first polyester polymerand a second polyester polymer having a lower crystallinity than thefirst polyester polymer. It has been found that incorporating a second,less crystalline polyester to a composition containing a first, morecrystalline polyester and carbon fibers improves the mechanicalproperties of the composition. Of particular advantage, when thiscombination is used, the mechanical properties of a carbon fiberreinforced polyester can be improved without the use of a sizing agenton the carbon fibers.

The polyesters which are suitable for use herein are derived from analiphatic or cycloaliphatic diol, or mixtures thereof, containing from 2to about 10 carbon atoms and an aromatic dicarboxylic acid, i.e.,polyalkylene terephthalates.

The polyesters which are derived from a cycloaliphatic diol and anaromatic dicarboxylic acid are prepared by condensing either the cis- ortrans-isomer (or mixtures thereof) of, for example,1,4-cyclohexanedimethanol with the aromatic dicarboxylic acid.

Examples of aromatic dicarboxylic acids include isophthalic orterephthalic acid, 1,2-di(p-carboxyphenyl)ethane, 4,4′-dicarboxydiphenylether, etc., and mixtures of these. Ail of these acids contain at leastone aromatic nucleus. Fused rings can also be present such as in 1,4- or1,5- or 2,6-naphthalene-dicarboxylic acids. In one embodiment, thedicarboxylic acid is terephthalic acid or mixtures of terephthalic andisophthalic acid.

Polyesters that may be used in the polymer composition, for instance,include polyethylene terephthalate, polybutylene terephthalate, mixturesthereof and copolymers thereof.

As described above, the composition may comprise a first polyester and asecond polyester with a lower crystallinity than the first polyester.For example, the first polyester may have a crystallinity greater thanabout 40%, such as greater than about 45%. The second, less crystallinepolyester may have a crystallinity less than about 40%, such as lessthan about 35%.

Percent crystallinity may be determined using differential scanningcalorimetry (DSC). Such analysis may be performed using a Pyris 6 DSCfrom PerkinElmer instruments. A detailed description of the calculationis available from Sichina, W. J. “DSC as problem solving tool:measurement of percent crystallinity of thermoplastics.” ThermalAnalysis Application Note (2000).

Those skilled in the art will appreciate that the degree ofcrystallinity of a given polyester may depend upon the monomers used toform the polymer, the process temperatures during formation of thepolymer, the process used to make the polymer, and/or the molecularstructure of the polyester. In one embodiment, the degree ofcrystallinity of a polyester can be altered by changing the amountand/or type and/or distribution of monomer units that make up thepolyester chain. For example, if about 3 to about 15 mole percent of theethylene glycol repeat units in poly ethylene terephthalate are replacedwith 1,4-cyclohexanedimethanol repeat units, or by di-ethylene glycolrepeat units, the resulting modified polyester can be amorphous and hasa low melt processing temperature. Similarly, if about 10 to about 20mole percent of the terephthalic acid repeat units in polyethyleneterephthalate (or polybutylene terephthalate) are replaced withisophthalic acid repeat units, the resulting modified polyester can alsobe amorphous and have a low melt processing temperature. Such conceptscan also be combined into one polyester or by melt mixing at least twodifferent polyesters. Accordingly, the choice of a particular modifyingacid or dial can significantly affect the melt processing properties ofthe polyester.

As used herein, the terms “modifying acid” and “modifying diol” aremeant to define compounds, which can form part of the acid and diolrepeat units of a polyester, respectively, and which can modify apolyester to reduce its crystallinity or render the polyester amorphous.In one embodiment, however, the polyesters present in the polymercomposition of the present disclosure are non-modified and do notcontain a modifying acid or a modifying dial.

Examples of modifying acid components may include, but are not limitedto, isophthalic acid, phthalic acid, 1,3-cyclohexanedicarboxylic acid,1,4-cyclohexane dicarboxylic acid, 2,6-naphthaline dicarboxylic acid,succinic acid, glutaric acid, adipic acid, sebacic acid, suberic acid,1,12-dodecanedioic acid, and the like. In practice, it is oftenpreferable to use a functional acid derivative thereof such as thedimethyl, diethyl, or dipropyl ester of the dicarboxylic acid. Theanhydrides or acid halides of these acids also may be employed wherepractical. Preferred is isophthalic acid.

Examples of modifying diol components may include, but are not limitedto, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,2-propanediol,1,3-propanediol, 2-Methy-1,3-propanediol, 1,4-butanediol,1,6-hexanediol, 1,2-cyclohexanediol, 1,4-cyclohexanediol,1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol,2,2,4,4-tetramethyl 1,3-cyclobutane diol,Z,8-bis(hydroxymethyltricyclo-[5.2.1.0]-decane wherein Z represents 3,4, or 5; 1,4-Bis(2-hydroxyethoxy)benzene, 4,4′-Bis(2-hydroxyethoxy)diphenylether [Bis-hydroxyethyl Bisphenol A],4,4′-Bis(2-hydroxyethoxy)diphenylsulfide [Bis-hydroxyethyl Bisphenol S]and diols containing one or more oxygen atoms in the chain, e.g.diethylene glycol, triethylene glycol, dipropylene glycol, tripropyleneglycol, and the like. In general, these diols contain 2 to 18,preferably 2 to 8 carbon atoms. Cycloalphatic diols can be employed intheir cis or trans configuration or as mixtures of both forms.

Other suitable low melt processing polyesters are based on polyadditionof lactones, for example poly-c-caprolacton.

The at least one polyester or copolyester present in the composition cangenerally have an intrinsic viscosity (IV) of from about 0.5 to about0.9 dL/g, such as from about 0.5 to about 0.8 dL/g. In one embodiment,for instance, the intrinsic viscosity of the polyester is from about0.65 to about 0.8 dL/g.

The at least one polyester is present in the polymer composition in anamount sufficient to form a continuous phase. For example, the polyestermay be present in the polymer composition in an amount of at least about25% by weight, such as in an amount of at least about 30% by weight,such as in an amount of at least 35% by weight, such as in an amount ofat least about 40% by weight, such as at least about 50% by weight, suchas at least about 60% by weight. The thermoplastic polymer is generallypresent in an amount less than about 95% by weight.

When using a first polyester and a second polyester having a lowercrystallinity than the first polyester, the first polyester may bepresent in an amount greater than about 25% by weight, such as greaterthan about 40% by weight. The first polyester is generally present in anamount less than about 93% by weight. The second polyester may bepresent in an amount less than 50% by weight, such as less than 40% byweight, preferably between about 2% to about 35% by weight.

In a particularly preferred embodiment, the first polyester ispolybutylene terephthalate (PBT) and the second, less crystallinepolyester is polyethylene terephthalate (PET). The polybutyleneterephthalate may have a crystallinity of greater than about 38%, suchas greater than about 40%, such as greater than about 45%. Thecrystallinity of the polybutylene terephthalate is generally less thanabout 70%. The polyethylene terephthalate, on the other hand, can have acrystallinity of less than about 40%, such as less than about 38%, suchas less than about 35%, such as less than 32%. The crystallinity of thepolyethylene terephthalate is generally greater than 0%, such as greaterthan 5%.

The polymer composition can also have excellent impact resistance. Forinstance, when tested according to the notched Charpy test at 23° C.,the polymer composition may have an impact resistance of at least about25 kJ/m², such as at least about 30 kJ/m², such as at least about 35kJ/m², such as at least about 40 kJ/m², such as at least about 45 kJ/m²,such as at least about 50 kJ/m² (generally less than 65 kJ/m², such asless than 60 kJ/m²). It has been surprisingly found that when a lesscrystalline polyester is incorporated into a composition including amore crystalline polyester and carbon fibers, the impact strength isimproved. 16270780In accordance with the present disclosure, acomposition is provided which includes a blend of a first polyester anda second less crystalline polyester present in a weight ratio in therange of about 50:1 to 5:7, preferably between about 5:1 and 3:4, evenmore preferably between about 5:1 to 8:5, said blend of first polyesterand second polyester present in a concentration in the ratio of betweenabout 55% and 95% by weight, preferably between about 60% and 90% byweight based on the total weight of the composition. The compositionincludes carbon fibers generally in an amount greater than about 5% byweight, such as in an amount greater than about 8% by weight, such as inan amount greater than about 10% by weight, such as in an amount greaterthan about 12% by weight, such as in an amount greater than about 15% byweight. The carbon fibers are present in the polymer compositiongenerally in an amount less than about 45% by weight, such as in anamount less than about 40% by weight, such as in an amount less thanabout 35% by weight, such as in an amount less than about 30% by weight.

The carbon fibers present in the composition can be recycled carbonfibers. For example, carbon fibers which have been formed into a carbonfiber fabric, but which have not been impregnated by a polymer, may bebroken down into individual carbon fibers, especially short carbonfibers. An example of a process for recycling carbon fibers into shortcarbon fiber lengths is disclosed by German Patent Application DE102009023529, which is incorporated herein by reference.

The carbon fibers present in the composition can be short carbon fibershaving a mean fiber length up to about 1,000 microns. In one embodiment,the carbon fibers have a mean fiber length of up to about 700 microns,such as between about 50 microns and 500 microns. For example, the meanfiber length before compounding may be less than about 700 microns, suchas less than about 500 microns, and also greater than about 100 microns.After compounding, the mean fiber length may be, for example, less thanabout 500 microns, such as less than about 400 microns, such as lessthan about 300 microns. In another embodiment, carbon fibers having amean length from about 50 to about 500 microns and are present in thecomposition in an amount from about 8% to about 35% by weight based onthe total weight of the composition.

In addition to the at least one polyester and the carbon fibers, thecomposition may also contain any number of desired additives,

For example, the composition may further include a nucleating agent,present in a concentration of between about 0.1 and 2% by weight,preferably between about 0,001% and 0.5% based on the total weight ofthe composition. The nucleating agent can be selected from the groupconsisting of alkali metal salts having anions which are oxides of theelements from Group IV of the Periodic Table; barium sulfate; and talc.

The polymer composition may also contain at least one stabilizer. Thestabilizer may comprise an antioxidant, a light stabilizer such as anultraviolet light stabilizer, a thermal stabilizer, and the like.

Sterically hindered phenolic antioxidant(s) may be employed in thecomposition. Examples of such phenolic antioxidants include, forinstance, calcium bis(ethyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate) (Irganox® 1425);terephthalic acid,1,4-dithio-,S,S-bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) ester(Cyanox® 1729); triethylene glycolbis(3-tert-butyl-4-hydroxy-5-methylhydrocinnamate); hexamethylenebis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate (Irganox® 259);1,2-bis(3,5,di-tert-butyl-4-hydroxyhydrocinnamoyphydrazide (Irganox®1024); 4,4′-di-tert-octyldiphenamine (Naugalube® 438R); phosphonic add,(3,5-di-tert-butyl-4-hydroxybenzyl)-,dioctadecyl ester (Irganox® 1093);1,3,5-trimethyl-2,4,6-tris(3′,5′-di-tert-butyl-4′ hydroxybenzyl)benzene(Irganox® 1330);2,4-bis(octylthio)-8-(4-hydroxy-3,5-di-tert-butylanilino)-1,3,5-triazine(Irganox® 565); isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate(Irganox® 1135); octadecyl3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Irganox® 1076);3,7-bis(1,1,3,3-tetramethylbutyl)-10H-phenothiazine (Irganox® LO 3);2,2′-methylenebis(4-methyl-6-tert-butylphenol)monoacrylate (Irganox®3052);2-tert-butyl-6-[1-(3-tert-butyl-2-hydroxy-5-methylphenyl)ethyl]-4-methylphenylacrylate (Sumilizer® TM 4039);2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenylacrylate (Sumilizer® GS); 1,3-dihydro-2H-Benzimidazole (Sumilizer® MB);2-methyl4,6-bis[(octylthio)methyl]phenol (Irganox® 1520);N,N′-trimethylenebis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide(Irganox® 1019); 4-n-octadecyloxy-2,6-diphenylphenol (Irganox® 1063);2,2′-ethylidenebis[4,6-di-tert-butylphenol] (Irganox® 129);N,N′-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyhydrocinnamide)(Irganox® 1098); diethyl (3,5-di-tert-butyl-4-hydroxybenxyl)phosphonate(Irganox® 1222); 4,4′-di-tert-octyldiphenylamine (Irganox® 5057);N-phenyl-1-napthalenamine (Irganox® L 05);tris[2-tert-butyl-4-(3-ter-butyl-4-hydroxy-6-methylphenylthio)-5-methylphenyl]phosphite (Hostanox® OSP 1); zinc dinonyidithiocarbamate(Hostanox® VP-ZNCS 1);3,9-bis[1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecaneAG80); pentaerythrityltetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox®1010);ethylene-bis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)-propionate(Irganox® 245); 3,5-di-tert-butyl-4-hydroxytoluene (Lowinox BHT,Chemtura) and so forth.

Some examples of suitable sterically hindered phenolic antioxidants foruse in the present composition are triazine antioxidants having thefollowing general formula:

wherein, each R is independently a phenolic group, which may be attachedto the triazine ring via a C₁ to C₅ alkyl or an ester substituent.Preferably, each R is one of the following formula (I)-(III):

Commercially available examples of such triazine-based antioxidants maybe obtained from American Cyanamid under the designation Cyanox® 1790(wherein each R group is represented by the Formula III) and from CibaSpecialty Chemicals under the designations Irganox® 3114 (wherein each Rgroup is represented by the Formula I) and Irganox® 3125 (wherein each Rgroup is represented by the Formula II).

Sterically hindered phenolic antioxidants may constitute from about 0.01wt. % to about 3 wt. %, in some embodiments from about 0.05 wt. % toabout 1 wt. %, and in some embodiments, from about 0.05 wt. % to about0.1 wt. % of the entire stabilized polymer composition. In oneembodiment, for instance, the antioxidant comprises pentaerythrityltetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

Hindered amine light stabilizers (“HALS”) may be employed in thecomposition to inhibit degradation of the polyester composition and thusextend its durability. Suitable HALS compounds may be derived from asubstituted piperidine, such as alkyl-substituted piperidyl,piperidinyl, piperazinone, alkoxypiperidinyl compounds, and so forth.For example, the hindered amine may be derived from a2,2,6,6-tetraalkylpiperidinyl. Regardless of the compound from which itis derived, the hindered amine is typically an oligomeric or polymericcompound having a number average molecular weight of about 1,000 ormore, in some embodiments from about 1000 to about 20,000, in someembodiments from about 1500 to about 15,000, and in some embodiments,from about 2000 to about 5000. Such compounds typically contain at leastone 2,2,6,6-tetraalkylpiperidinyl group (e.g., 1 to 4) per polymerrepeating unit.

Without intending to be limited by theory, it is believed that highmolecular weight hindered amines are relatively thermostable and thusable to inhibit light degradation even after being subjected toextrusion conditions. One particularly suitable high molecular weighthindered amine has the following general structure:

wherein, p is 4 to 30, in some embodiments 4 to 20, and in someembodiments 4 to 10. This oligomeric compound is commercially availablefrom Clariant under the designation Hostavin® N30 and has a numberaverage molecular weight of 1200.

Another suitable high molecular weight hindered amine has the followingstructure:

wherein, n is from 1 to 4 and R₃₀ is independently hydrogen or CH₃. Sucholigomeric compounds are commercially available from Adeka Palmarole SAS(joint venture between Adeka Corp. and Palmarole Group) under thedesignation ADK STAB® LA-63 (R₃₀ is CH₃) and ADK STAB® LA-68 (R₃₀ ishydrogen).

Other examples of suitable high molecular weight hindered aminesinclude, for instance, an oligomer ofN-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-piperidinol and succinic acid(Tinuvin® 622 from Ciba Specialty Chemicals, MW=4000); oligomer ofcyanuric acid and N,N-di(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylenediamine;poly((6-morpholine-S-triazine-2,4-diyl)(2,2,6,6-tetramethyl-4-piperidinyl)-iminohexamethylene-(2,2,6,6-tetramethyl-4-piperidinyl)-imino)(Cyasorb® UV 3346 from Cytec, MW=1600);polymethylpropyl-3-oxy-[4(2,2,6,6-tetramethyl)-piperidinylysiloxane(Uvasil® 299 from Great Lakes Chemical, MW=1100 to 2500); copolymer ofα-methylstyrene-N-(2,2,6,6-tetramethyl-4-piperidinyl)maleimide andN-stearyl maleimide: 2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diethanoltetramethyl-polymer with 1,2,3,4-butanetetracarboxylic acid; and soforth. Still other suitable high molecular weight hindered amines aredescribed in U.S. Pat. No. 5,679,733 to Malik, et al. and U.S. Pat. No.6,414,155 to Sassi, et al., which are incorporated herein in theirentirety by reference thereto for all purposes.

In addition to the high molecular hindered amines, low molecular weighthindered amines may also be employed in the composition. Such hinderedamines are generally monomeric in nature and have a molecular weight ofabout 1000 or less, in some embodiments from about 155 to about 800, andin some embodiments, from about 300 to about 800.

Specific examples of such low molecular weight hindered amines mayinclude, for instance, bis-(2,2,6,6-tetramethyl-4-piperidyl) sebacate(Tinuvin® 770 from Ciba Specialty Chemicals, MW-481);bis-(1,2,2,6,6-pentamethyl-4-piperidinyl)-(3,5-ditert,butyl-4-hydroxybenzyl)butyl-propanedioate; bis-(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate;8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro-(4,5)-decane-2,4-dione,butanedioic acid-bis-(2,2,6₂6-tetramethyl-4-piperidinyl) ester;tetrakis-(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate; 7-oxo-3,20-diazadispiro(5.1.11.2)beneicosan-20-propanoic acid, 2,2,4,4-tetramethyl-21-oxo, dodecyl ester;N-(2,2,6,6-tetramethyl-4-piperidinyl)-N′-amino-oxamide;o-t-amyl-o-(1,2,2,6,6-pentamethyl-4-piperidinyl)-monoperoxi-carbonate;β-alanine, N-(2,2,6,6-tetramethyl-4-piperidinyl), dodecylester;ethanediamide, N-(1-acetyl-2,2,6,6-tetramethylpiperidinyl)-N′-dodecyl;3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidinyl)-pyrrolidin-2,5-dione;3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidinyl)-pyrrolidin-2,5-dione;3-dodecyl-1-(1-acetyl,2,2,6,6-tetramethyl-4-piperidinyl)-pyrrolidin-2,5-dione,(Sanduvar® 3058 from Clariant, MW=448.7);4-benzoyloxy-2,2,6,6-tetramethylpiperidine;1-[2-(3,5-di-tert-butyl-4-hydroxyphenylpropionyloxy)ethyl]-4-(3,5-di-tert-butyl-4-hydroxylphenylpropionyloxy)-2,2,6,6-tetramethyl-piperidine;2-methyl-2-(2″,2″,6″,6″-tetramethyl-4″-piperidinylamino)-N-(2′,2′,6′,6′-tetra-methyl-4′-piperidinyl)propionylamide;1,2-bis-(3,3,5,5-tetramethyl-2-oxo-piperazinyl)ethane;4-oleoyloxy-2,2,6,6-tetramethylpiperidine; and combinations thereof.Other suitable low molecular weight hindered amines are described inU.S. Pat. No. 5,679,733 to Malik, et al,

The hindered amines may be employed singularly or in combination in anyamount to achieve the desired properties, but typically constitute fromabout 0.01 wt. % to about 4 wt. % of the polymer composition.

UV absorbers, such as benzotriazoles or benzopheones, may be employed inthe composition to absorb ultraviolet light energy. Suitablebenzotriazoles may include, for instance,2-(2-hydroxyphenyl)benzotriazoles such as2-(2-hydroxy-5-methylphenyl)benzotriazole;2-(2-hydroxy-5-tert-octylphenyl)benzotriazole (Cyasorb® UV 5411 fromCytec); 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzo-triazole;2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole;2-(2-hydroxy-3,5-dicumylphenyl)benzotriazole;2,2′-methylenebis(4-tert-octyl-6-benzo-triazolylphenol); polyethyleneglycol ester of 2-(2-hydroxy-3-tert-butyl-5-carboxyphenyl)benzotriazole;2-[2-hydroxy-3-(2-acryloyloxyethyl)-5-methylphenyl]-benzotriazole;2-[2-hydroxy-3-(2-methacryloyloxyethyl)-5-tert-butylphenyl]benzotriazole;2-[2-hydroxy-3-(2-methacryloyloxyethyl)-5-tert-octylphenyl]benzotriazole;2-[2-hydroxy-3-(2-methacryloyloxyethyl)-5-tert-butylphenyl]-5-chlorobenzotriazole;2-[2-hydroxy-5-(2-methacryloyloxyethyl)phenyl]benzotriazole;2-[2-hydroxy-3-tert-butyl-5-(2-methacryloyloxyethyl)phenyl]benzotriazole;2-[2-hydroxy-3-tert-amyl-5-(2-methacryloyloxyethyl)phenyl]benzotriazole;2-[2-hydroxy-3-tert-butyl-5-(3-methacryloyloxypropyl)phenyl]-5-chlorobenzotriazole;2-[2-hydroxy-4-(2-methacryloyloxymethyl)phenyl]benzotriazole;2-[2-hydroxy-4-(3-methacryloyloxy-2-hydroxypropyl)phenyl]benzotriazole;2-[2-hydroxy-4-(3-methacryloyloxypropyl)phenyl]benzotriazole; andcombinations thereof.

Exemplary benzophenone light stabilizers may likewise include2-hydroxy-4-dodecyloxybenzophenone; 2,4-dihydroxybenzophenone;2-(4-benzoyl-3-hydroxyphenoxy)ethyl acrylate (Cyasorb® UV 209 fromCytec); 2-hydroxy-4-n-octyloxy)benzophenone (Cyasorb® 531 from Cytec);2,2′-dihydroxy-4-(octyloxy)benzophenone (Cyasorb® UV 314 from Cytec);hexadecyl-3,5-bis-tert-butyl-4-hydroxybenzoate (Cyasorb® UV 2908 fromCytec); 2,2′-thiobis(4-tert-octylphenolato)-n-butylamine nickel(II)(Cyasorb® UV 1084 from Cytec); 3,5-di-tert-butyl-4-hydroxybenzoic acid,(2,4-di-tert-butylphenyl)ester (Cyasorb® 712 from Cytec);4,4′-dimethoxy-2,2° -dihydroxybenzophenone (Cyasorb® UV 12 from Cytec);and combinations thereof.

When employed, UV absorbers may constitute from about 0.01 wt. % toabout 4 wt. % of the entire polymer composition.

In one embodiment, the polymer composition may contain a blend ofstabilizers that produce ultraviolet resistance and color stability. Thecombination of stabilizers may allow for products to be produced thathave bright and fluorescent colors. In addition, bright colored productscan be produced without experiencing significant color fading over time.In one embodiment, for instance, the polymer composition may contain acombination of a benzotriazole light stabilizer and a hindered aminelight stabilizer, such as an oligomeric hindered amine.

Various other stabilizers may also be present in the composition. Forinstance, in one embodiment, the composition may contain a phosphite,such as a diphosphite. For instance, in one embodiment, the phosphitecompound may comprise distearyl pentaerythritol diphosphite. Thephosphite compound may also comprisebis(2,4-ditert-butylphenyl)pentaerythritol diphosphite.

Organophosphorus compounds may be employed in the composition that serveas secondary antioxidants to decompose peroxides and hydroperoxides intostable, non-radical products. Trivalent organophosphorous compounds(e.g., phosphites or phosphorites) are particularly useful in thestabilizing system of the present invention. Monophosphite compoundsonly one phosphorus atom per molecule) may be employed in certainembodiments of the present invention. Preferred monophosphites are arylmonophosphites contain C₁ to C₁₀ alkyl substituents on at least one ofthe aryloxide groups. These substituents may be linear (as in the caseof nonyl substituents) or branched (such as isopropyl or tertiary butylsubstituents). Non-limiting examples of suitable aryl monophosphites (ormonophosphonites) may include triphenyl phosphite; diphenyl alkylphosphites; phenyl dialkyl phosphites; tris(nonylphenyl) phosphite(Weston™ 399, available from GE Specialty Chemicals);tris(2,4-di-tert-butylphenyl) phosphite (Irgafos® 168, available fromCiba Specialty Chemicals Corp.):bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite (Irgafos® 38,available from Ciba Specialty Chemicals Corp.); and2,2′,2″-nitrilo[triethyltris(3,3′,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)phosphate (Irgafos® 12, available from Ciba Specialty Chemicals Corp.).Aryl diphosphites or diphosphonites (i.e., contains at least twophosphorus atoms per phosphite molecule may also be employed in thestabilizing system and may include, for instance, distearylpentaerythritol diphosphite, diisodecyl pentaerythritol diphosphite,bis(2,4 di-tert-butylphenyl) pentaerythritol diphosphite (Ultranox™ 626,available from GE Specialty Chemicals);bis(2,6-di-tert-butyl-4-methylpenyl)pentaerythritol diphosphite;bisisodecyloxypentaerythritol diphosphite,bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite,bis(2,4,6-tri-tert-butylphenyl)pentaerythritol diphosphite,tetrakis(2,4-di-tert-butylphenyl)4,4′-biphenylene-diphosphonite(Sandostab™ P-EPQ, available from Clariant) andbis(2,4-dicumylphenyl)pentaerythritol diphosphite (Doverphos® S-9228)

Organophosphorous compounds may constitute from about 0.01 wt. % toabout 2 wt. %, in some embodiments from about 0.05 wt. % to about 1 wt.%, and in some embodiments, from about 0.1 wt. % to about 0.5 wt. % ofthe polymer composition.

In addition to those mentioned above, secondary amines may also beemployed in the composition. The secondary amines may be aromatic innature, such as N-phenyl naphthylamines (e.g., Naugard® PAN fromUniroyal Chemical); diphenylamines, such as4,4′-bis(dimethylbenzyl)-diphenylamine (e.g., Naugard® 445 from UniroyalChemical); p-phenylenediamines (e.g., Wingstay® 300 from Goodyear);quinolones, and so forth. Particularly suitable secondary amines areoligomeric or polymeric amines, such as homo- or copolymerizedpolyamides. Examples of such polyamides may include nylon 3(poly-alanine), nylon 6, nylon 10, nylon 11, nylon 12, nylon 6/6, nylon6/9, nylon 6/10, nylon 6/11, nylon 6/12, polyesteramide, polyamideimide,polyacrylamide, and so forth. In one particular embodiment, the amine isa polyimide terpolymer having a melting point in the range from 120° C.to 220° C. Suitable terpolymers may be based on the nylons selected fromthe group consisting of nylon 6, nylon 6/6, nylon 6/9, nylon 6/10 andnylon 6/12, and may include nylon 6-66-69; nylon 6-66-610 and nylon6-66-612, One example of such a nylon terpolymer is a terpolymer ofnylon 6-66-610 and is commercially available from Du Pont de Nemoursunder the designation Elvamide® 8063R. Still other suitable aminecompounds are described in U.S. Patent Application Publication No.2003/0060529 to Ho, et al., which is incorporated herein in its entiretyby reference thereto for all purposes.

Secondary amines may constitute from about 0.01 wt. % to about 2 wt. %,of the entire polymer composition.

If desired, other known stabilizers may also be incorporated into thecomposition, such as metal deactivators, acid stabilizers, other lightstabilizers (e.g., benzophenones) or antioxidants, etc. Acidstabilizers, for instance, may help neutralize the acidic catalysts orother components present in the polymers. Suitable acid stabilizers mayinclude zinc oxide, calcium lactate, natural and synthetichydrotalcites, natural and synthetic hydrocalumites, and alkali metalsalts and alkaline earth metal salts of higher fatty acids, such ascalcium stearate, zinc stearate, magnesium stearate, sodium stearate,sodium ricinoleate and potassium palmitate. When employed, such addstabilizers typically constitutes about 1.5 wt. % or less, in someembodiments, about 1 wt. % or less, and in some embodiments, from about0.01 wt. % to about 0.5 wt. % of the polymer composition.

Each stabilizer above may be present in an amount from about 0.01% toabout 3% by weight, such as from about 0.05% to about 0.5% by weight. Ina preferred embodiment, the composition contains both a heat stabilizerand an antioxidant. For example, the heat stabilizer may comprise asterically hindered phenolic compound and the antioxidant may comprise adiphosphite.

In addition to any stabilizer present in the composition, thethermoplastic copolyester composition of the present invention may alsoinclude a lubricant that constitutes from about 0.01 wt. % to about 2wt. %, in some embodiments from about 0.1 wt. % to about 1 wt. %, and insome embodiments, from about 0.2 wt. % to about 0.5 wt. % of the polymercomposition. The lubricant may be formed from a fatty add salt derivedfrom fatty adds having a chain length of from 22 to 38 carbon atoms, andin some embodiments, from 24 to 36 carbon atoms. Examples of such fattyadds may include long chain aliphatic fatty adds, such as montanic add(octacosanoic add), arachidic add (arachic add, icosanic add, icosanoicadd, n-icosanoic add), tetracosanoic add (lignoceric add), behenic add(docosanoic add), hexacosanoic add (cerotinic add), melissic add(triacontanoic add), erucic add, cetoleic add, brassidic add,selacholeic add, nervonic add, etc. For example, montanic add has analiphatic carbon chain of 28 atoms and arachidic add has an aliphaticcarbon chain of 20 atoms. Due to the long carbon chain provided by thefatty add, the lubricant has a high thermostability and low volatility.This allows the lubricant to remain functional during formation of thedesired article to reduce internal and external friction, therebyreducing the degradation of the material caused by mechanical/chemicaleffects.

The fatty add salt may be formed by saponification of a fatty add wax toneutralize excess carboxylic adds and form a metal salt. Saponificationmay occur with a metal hydroxide, such as an alkali metal hydroxide(e.g., sodium hydroxide) or alkaline earth metal hydroxide (e.g.,calcium hydroxide). The resulting fatty acid salts typically include analkali metal (e.g., sodium, potassium, lithium, etc.) or alkaline earthmetal (e.g., calcium, magnesium, etc.). Such fatty acid salts generallyhave an add value (ASTM D 1386) of about 20 mg KOH/g or less, in someembodiments about 18 mg KOH/g or less, and in some embodiments, fromabout 1 to about 15 mg KOH/g. Particularly suitable fatty add salts foruse in the present invention are derived from crude montan wax, whichcontains straight-chain, unbranched monocarboxylic adds with a chainlength in the range of C₂₈-C₃₂. Such montanic add salts are commerciallyavailable from Clariant GmbH under the designations Licomont® CaV 102(calcium salt of long-chain, linear montanic adds) and Licomont® NaV 101(sodium salt of long-chain, linear montanic adds).

If desired, fatty add esters may be used as lubricants. Fatty add estersmay be obtained by oxidative bleaching of a crude natural wax andsubsequent esterification of the fatty adds with an alcohol. The alcoholtypically has 1 to 4 hydroxyl groups and 2 to 20 carbon atoms. When thealcohol is multifunctional (e.g., 2 to 4 hydroxyl groups), a carbon atomnumber of 2 to 8 is particularly desired. Particularly suitablemultifunctional alcohols may include dihydric alcohol (e.g., ethyleneglycol, propylene glycol, butylene glycol, 1,3-propanediol,1,4-butanediol, 1,6-hexanediol and 1,4-cyclohexanediol), trihydricalcohol (e.g., glycerol and trimethylolpropane), tetrahydric alcohols(e.g., pentaerythritol and erythritol), and so forth. Aromatic alcoholsmay also be suitable, such as o-, m- and p-tolylcarbinol, chlorobenzylalcohol, bromobenzyl alcohol, 2,4-dimethylbenzyl alcohol,3,5-dimethylbenzyl alcohol, 2,3,5-cumobenzyl alcohol,3,4,5-trimethylbenzyl alcohol, p-cuminyl alcohol, 1,2-phthalyl alcohol,1,3-bis(hydroxymethyl)benzene, 1,4-bis(hydroxymethyl)benzene,pseudocumenyl glycol, mesitylene glycol and mesitylene glycerol.Particularly suitable fatty add esters for use in the present inventionare derived from montanic waxes. Licowax® OP (Clariant), for instance,contains montanic adds partially esterified with butylene glycol andmontanic acids partially saponified with calcium hydroxide. Thus,Licowax® OP contains a mixture of montanic add esters and calciummontanate. Other montanic add esters that may be employed includeLicowax® E, Licowax® OP, and Licolub® WE 4 (all from Clariant), forinstance, are montanic esters obtained as secondary products from theoxidative refining of raw montan wax. Licowax® E and Licolub®WE 4contain montanic adds esterified with ethylene glycol or glycerine.Still other suitable montan wax derivatives may be described in U.S.Pat. No. 5,096,951, as well as in U.S. Patent Application PublicationNos. 2007/0073007; 2006/0100330; and 2004/0254280, all of which areincorporated herein in theft entirety by reference thereto for allpurposes.

Other known waxes may also be employed in a lubricant. Amide waxes, forinstance, may be employed that are formed by reaction of a fatty acidwith a monoamine or diamine (e.g., ethylenediamine) having 2 to 18,especially 2 to 8, carbon atoms. For example, ethylenebisamide wax,which is formed by the amidization reaction of ethylene diamine and afatty acid, may be employed. The fatty acid may be in the range from C₁₂to C₃₀, such as from stearic acid (C₁₈ fatty acid) to formethylenebisstearamide wax. Ethylenebisstearamide wax is commerciallyavailable from Lonza Inc. under the designation Acrawax® C, which has adiscrete melt temperature of 142° C. Other ethylenebisamides include thebisamides formed from lauric acid, palmitic acid, oleic acid, linoleicacid, linolenic acid, oleostearic acid, myristic acid and undecalinicacid. Still other suitable amide waxes areN-(2-hydroxyethyl)12-hydroxystearamide and N,N′-(ethyleriebis)12-hydroxystearamide, which are commercially available from CasChem,a division of Rutherford Chemicals LLC, under the designations Paricin®220 and Paricin® 285, respectively.

In one embodiment, the carbon fiber reinforced polymer compositioncomprises a polybutylene terephthalate polyester, a fatty acid ester, anucleant, a heat stabilizing agent, and an antioxidant in addition tofibers having a mean fiber length of from about 10 microns to about1,000 microns. The polybutylene terephthalate may be present in thecomposition in an amount from about 35% to about 90% by weight. Thecomposition optionally includes a second polyester having a lowercrystallinity than the polybutylene terephthalate. In a particularlypreferred embodiment, the second, less crystalline polyester ispolyethylene terephthalate.

In addition to the above components, the polymer composition may includevarious other ingredients. Colorants that may be used include anydesired inorganic pigments, such as titanium dioxide, ultramarine blue,cobalt blue, and other organic pigments and dyes, such asphthalocyanines, anthraquinones, and the like. Other colorants includecarbon black or various other polymer-soluble dyes. The colorants cangenerally be present in the composition in an amount up to about 2percent by weight.

The present disclosure may be better understood with reference to thefollowing examples.

EXAMPLES

Various polymer compositions were formulated in accordance with thepresent disclosure and tested for various properties. The amount ofrecycled carbon fiber added to the compositions varied. The followingresults were obtained.

TABLE 1 10% Recycled CF Sample No. Norm Formulation ISO Unit 1 2 3 4 5 6Polybutylene % 86 86 85.5 85.5 71 71 Terephthalate MVR38 Montanic acidtriol ester % 0.25 0.25 0.25 0.25 0.25 0.25 nucleant (Talcum) % 0.150.15 0.15 0.15 0.15 0.15 Pentaerythritol tetrakis(3- % 0.08 0.08 0.080.08 0.08 0.08 (3,5-di-tert-butyl-4- hydroxyphenyl)propionate)Bis-(2,4-di-t-butylphenol) % 0.17 0.17 0.17 0.17 0.17 0.17Pentaerythritol Diphosphite Titanate coupling agent % 0 0 0.3 0.3 0 0Polyethylene 0 0 0 0 15 15 terephthalate Intrinsic Viscosity 0.77Polybutylene % 0.35 0.35 0.55 0.55 0.35 0.35 Terephthalate grindPolybutylene Terephthalate % 2 0 2 0 2 0 95076 black MasterbatchPolyethylene 950231 % 0 2 0 2 0 2 black masterbatch recycled carbonfiber r-CF % 11 11 11 11 11 11 Total % 100 100 100 100 100 100 ash* 1172% 12.09 12.42 12.69 11.77 12.27 14.55 MVR 250° C./2, 16 kg 1133 cm³/1022 21.6 27.2 min Tensile Modulus 527-1/2 MPa 8,896 7,540 8,759 7,7579062 8420 Tensile Strength 527-1/2 MPa 118 98 116 98.3 118 104.6Elongation @ Break 527-1/2 % 3.6 4.4 3 3.5 3.3 4.5 Charpy Impact 179/1eUkJ/m² 33 42.2 29 41.1 29 39.5 Strength @ 23° C. Density g/cm³ 1.3531.361 Spec. IEC Ohm 8.E+11 4.E+11 Surface Resistivity 60093 8.E+115.E+11 4.E+11 5.E+11 Spec. IEC Ohm · m 2.E+04 2.E+04 Volume Resistivity60093 9.E+04 1.E+04 9.E+04 1.E+04

TABLE 2 15% Recycled CF Sample No. Formulation Norm ISO Unit 7 8 9 10Polybutylene Terephthalate % 80.5 80.5 65.5 65.5 MVR38 Montanic acidtriol ester % 0.25 0.25 0.25 0.25 nucleant (Talcum) % 0.15 0.15 0.150.15 Pentaerythritol tetrakis(3- % 0.08 0.08 0.08 0.08(3,5-di-tert-butyl-4- hydroxyphenyl)propionate)Bis-(2,4-di-t-butylphenol) % 0.17 0.17 0.17 0.17 PentaerythritolDiphosphite Titanate coupling agent % 0 0 0 0 Polyethylene terephthalate0 0 15 15 Intrinsic Viscosity 0.77 Polybutylene Terephthalate % 0.350.35 0.35 0.35 grind Polybutylene Terephthalate % 2 0 2 0 95076 blackmasterbatch Polyethylene 950231 black % 0 2 0 2 masterbatch recycledcarbon fiber r-CF % 16.5 16.5 16.5 16.5 Total % 100 100 100 100 ash*1172 % 15.96 18.52 17.97 19.73 MVR 250° C./2, 16 kg 1133 cm³/10 min 18.621.5 Tensile Modulus 527-1/2 MPa 12,462 11,271 13110 12073 TensileStrength 527-1/2 MPa 139 121.4 142 125 Elongation @ Break 527-1/2 % 3.13.5 3 3.7 Charpy Impact 179/1eU kJ/m² 47 46.3 47.9 51.1 Strength @ 23°C. Density g/cm³ 1.372 1.376 Spec. IEC 60093 Ohm 8.E+03 4.E+04 SurfaceResistivity IEC 60093 Ohm 6.E+03 6.E+04 IEC 60093 Ohm 7.E+03 1.E+05Spec. IEC 60093 Ohm · m 4.E+01 2.E+02 Volume Resistivity IEC 60093 Ohm.m4.E+01 2.E+02 IEC 60093 Ohm · m 4.E+01 2.E+02

TABLE 3 20% Recycled CF Sample No. Norm Formulation ISO Unit 11 12 13 1415 16 Polybutylene % 75 75 75 55 55 55 Terephthalate MVR38 Montanic acidtriol ester % 0.25 0.25 0.25 0.25 0.25 0.25 nucleant (Talcum) % 0.150.15 0.15 0.15 0.15 0.15 Pentaerythritol tetrakis(3- % 0.08 0.08 0.080.08 0.08 0.08 (3,5-di-tert-butyl-4- hydroxyphenyl)propionate)Bis-(2,4-di-t-butylphenol % 0.17 0.17 0.17 0.17 0.17 0.17Pentaerythritol Diphosphite Polyethylene % 0 0 0 20 20 20 terephthalateIntrinsic Viscosity 0.77 Polybutylene % 0.35 0.35 0.35 0.35 0.35 0.35Terephthalate grind Polybutylene Terephthalate % 2 0 0 2 0 0 95076 blackmasterbatch Polyethylene 950231 % 0 2 2 0 2 2 black masterbatch recycledcarbon fiber r-CF % 22 22 22 22 22 22 Total % 100 100 100 100 100 100ash* 1172 % 22.48 22.87 23.4 23.6 23.94 25.12 MVR 250° C./2, 16 kg 1133cm³/10 min 14.7 17.1 Tensile Modulus 527-1/2 MPa 16,730 14,806 15,99217,145 14,972 16,930 Tensile Strength 527-1/2 MPa 158 140.3 156 163142.3 160 Elongation @ Break 527-1/2 % 2.3 2.6 2.8 2.5 3 2.8 CharpyImpact 179/1eU kJ/m² 48 48.3 52 51 53.4 53 Strength @ 23° C. Densityg/cm³ 1.393 1.400 1.405 1.400 Spec. IEC Ohm 4.E+01 1.E+03 SurfaceResistivity 60093 4.E+01 1.E+03 4.E+01 1.E+03 Spec. IEC Ohm · m 3.E+006.E+00 Volume Resistivity 60093 3.E+00 6.E+00 3.E+00 7.E+00

TABLE 4 30% Recycled CF Sample No. Norm Formulation ISO Unit 17 18 19 2020 22 Polybutylene % 64 64 64 39 39 39 Terephthalate MVR38 Montanic acidtriol ester % 0.25 0.25 0.25 0.25 0.25 0.25 nucleant (Talcum) % 0.150.15 0.15 0.15 0.15 0.15 Pentaerythritol tetrakis(3- % 0.08 0.08 0.080.08 0.08 0.08 (3,5-di-tert-butyl-4- hvdroxyphenyl)propionate)Bis-(2,4-di-t-butylphenol) % 0.17 0.17 0.17 0.17 0.17 0.17Pentaerythritol Diphosphite Polyethylene % 0 0 0 25 25 25 terephthalateIntrinsic Viscosity 0.77 Polybutylene % 0.35 0.35 0.35 0.35 0.35 0.35Terephthalate grind Polybutylene % 2 0 0 2 0 0 Terephthalate 95076 blackmasterbatch Polyethylene 950231 % 0 2 2 0 2 2 black masterbatch recycledCF % 33 33 33 33 33 33 Total % 100 100 100 100 100 100 ash* 1172 % 32.5234.11 33.73 34.26 34.98 35.3 MVR 250° C./2, 16 kg 1133 cm³/10 min 9.710.4 Tensile Modulus 527-1/2 MPa 24,272 22,679 23,338 25,400 23,34524,718 Tensile Strength 527-1/2 MPa 180 164.2 180 191 173.7 186Elongation @ Break 527-1/2 % 1.5 1.5 1.9 1.7 1.8 1.8 Charpy Impact179/1eU kJ/m² 49 47.9 55 54.4 55 57 Strength @ 23° C. Density g/cm³1.432 1.440 1.452 1.440 Spec. IEC Ohm 4.E+01 6.E+01 Surface Resistivity60093 4.E+01 6.E+01 4.E+01 7.E+01 Spec. IEC Ohm · m 4.E−01 8.E−01 VolumeResistivity 60093 5.E−01 8.E−01 4.E−01 8.E−01

TABLE 5 40% Recycled CF Sample No. Norm Formulation ISO Unit 23 24 25 2627 28 Polybutylene Terephthalate % 53 53 53 23 23 23 MVR38 Montanic acidtriol ester % 0.25 0.25 0.25 025 0.25 0.25 nucleant (Talcum) % 0.15 0.150.15 0.15 0.15 0.15 Pentaerythritol tetrakis(3- % 0.08 0.08 0.08 0.080.08 0.08 (3,5-di-tert-buty1-4- hydroxyphenyl)propionate) Bis-(2,4-di-t-butylphenol) % 0.17 0.17 0.17 0.17 0.17 0.17 PentaerythritolDiphosphite Polyethylene terephthalate % 0 0 0 30 30 30 IntrinsicViscosity 0.77 Polybutylene Terephthalate % 0.35 0.35 0.35 0.35 0.350.35 grind Polybutylene Terephthalate % 2 0 0 2 0 0 95076 blackmasterbatch Polyethylene 950231 black % 0 2 2 0 2 2 masterbatch recycledcarbon fiber r-CF % 44 44 44 44 44 44 Total % 100 100 100 100 100 100ash* 1172 % 43.75 43.55 43.86 45.6 45.06 45.09 MVR 250° C./2, 16 kg 1133cm³/10 5.4 6.9 min Tensile Modulus 527-1/2 MPa 31,596 29,669 31,78733,937 32,039 32,371 Tensile Strength 527-1/2 MPa 182 171.2 189 204187.2 191 Elongation @ Break 527-1/2 % 1 1 1.1 1 1.1 1.1 Charpy ImpactStrength @ 179/1eU kJ/m² 43 43.6 55 49 48.3 52 23° C. Density g/cm³1.481 1.480 1.503 1.480 Spec. IEC Ohm 2.E+01 3.E+01 Surface Resistivity60093 2.E+01 3.E+01 2.E+01 3.E+01 Spec. IEC Ohm · 2.E−01 3.E−01 VolumeResistivity 60093 m 3.E−01 4.E−01 2.E−01 4.E−01

These and other modifications and variations to the present inventionmay be practiced by those of ordinary skill in the art, withoutdeparting from the spirit and scope of the present invention, which ismore particularly set forth in the appended claims. In addition, itshould be understood that aspects of the various embodiments may beinterchanged both in whole or in part. Furthermore, those of ordinaryskill in the art will appreciate that the foregoing description is byway of example only, and is not intended to limit the invention sofurther described in such appended claims.

What is claimed:
 1. A reinforced polymer composition comprising: a first polyester polymer; a second polyester polymer blended with the first polyester polymer, the second polyester polymer being less crystalline than the first polyester polymer, the second polyester polymer being present in the polymer composition in an amount from about 2% by weight to about 35% by weight; and carbon fibers combined with the first and second polyester polymers, the carbon fibers being present in the polymer composition in an amount from about 5% by weight to about 50% by weight, and wherein the carbon fibers have a mean fiber length of from about 10 microns to about 1,000 microns.
 2. A reinforced polymer composition as defined in claim 1, wherein the carbon fibers have a mean fiber length of from about 50 microns to about 500 microns.
 3. A reinforced polymer composition as defined in claim 1, wherein the carbon fibers have a mean fiber length of from about 50 microns to about 200 microns, and wherein the carbon fibers are present in the composition in an amount from about 10% to about 45% by weight.
 4. A reinforced polymer composition as defined in claim 1, wherein the carbon fibers are substantially free of a sizing agent.
 5. A reinforced polymer composition as defined in claim 1, wherein the first polyester polymer has a crystallinity of greater than about 40%.
 6. A reinforced polymer composition as defined in claim 1, wherein the second polyester polymer has a crystallinity of less than about 40%.
 7. A reinforced polymer composition as defined in claim 1, wherein the first polyester polymer comprises polybutylene terephthalate.
 8. A reinforced polymer composition as defined in claim 1, wherein the second polyester polymer comprises polyethylene terephthalate.
 9. A reinforced polymer composition as defined in claim 1, wherein the composition further contains a fatty acid ester.
 10. A reinforced polymer composition as defined in claim 9, wherein the fatty acid ester comprises an ester of montanic acid.
 11. A reinforced polymer composition as defined in claim 1, wherein the composition further contains a nucleating agent.
 12. A reinforced polymer composition as defined in claim 11, wherein the nucleating agent comprises talc and wherein the nucleating agent is present in the composition in an amount from about 0.001% to about 0.5% by weight.
 13. A reinforced polymer composition as defined in claim 1, wherein the composition contains a heat stabilizer and an antioxidant.
 14. A reinforced polymer composition as defined in claim 13, wherein the heat stabilizer comprises a diphosphate or triphosphite and wherein the antioxidant comprises a sterically hindered phenolic compound.
 15. A reinforced polymer composition as defined in claim 1, wherein the composition is in a compounded form.
 16. A reinforced polymer composition comprising: a polyester polymer comprising a polybutylene terephthalate polymer; a fatty acid ester blended with the polyester polymer; a nucleant blended with the polyester polymer; a heat stabilizing agent and an antioxidant blended with the polyester polymer; and carbon fibers combined with the polyester polymer, the carbon fibers being present in the polymer composition in an amount from about 5% to about 50% by weight, the carbon fibers having a mean fiber length of from about 50 microns to about 500 microns.
 17. A reinforced polymer composition as defined in claim 16, further comprising a second polyester polymer, the second polyester polymer being less crystalline than the polybutylene terephthalate polymer.
 18. A reinforced polymer composition as defined in claim 16, wherein the fatty acid ester comprises an ester of montanic acid.
 19. A reinforced polymer composition as defined in claim 16, wherein the nucleating agent comprises talc and wherein the nucleating agent is present in the composition in an amount from about 0.001% to about 0.5% by weight.
 20. A reinforced polymer composition as defined in claim 16, wherein the heat stabilizer comprises a diphosphate or triphosphite and wherein the antioxidant comprises a sterically hindered phenolic compound.
 21. A reinforced polymer composition as defined in claim 16, wherein the polybutylene terephthalate polymer is present in the composition in an amount from about 20% to about 90% by weight.
 22. A housing comprising: a molded polymer article defining a casing for enclosing an adjacent structure, the molded polymer article being made from a polymer composition comprising a first polyester polymer comprising polybutylene terephthalate and a second polyester polymer that is less crystalline than the first polyester polymer blended with the carbon fibers, the carbon fibers having a mean fiber length of from about 10 microns to about 1,000 microns, the polymer composition having a tensile strength of greater than 110 MPa, having a tensile modulus of greater than about 12,000 MPa, and having an elongation at break of greater than about 2%.
 23. A housing as defined in claim 22, wherein the housing is part of an automobile engine.
 24. A housing as defined in claim 22, wherein the housing is part of a windshield wiper assembly. 